In traditional formwork methods in the moulding of a concrete wall panel, in situations where a window or door opening is required to be formed in the panel, it is common practice for false formwork, normally constructed of timber, to be installed within the panel mould so that the false formwork defines the opening to be formed. The false timber formwork is nailed together and plastic fillet forming strips are attached to the timber formwork around parts of the formwork defining upper and lower perimetral parts of the opening. With the false formwork in place, the void or cavity defined by the false formwork is filled with either dirt/rubble or polystyrene foam, following which the concrete is poured into the mould to form the panel.
Such a procedure would not be suitable for casting concrete panels which are to have window/door openings formed therein, one on top of the other, mainly due to formwork imprints being left on the cast face of the upper panel. This necessitates carrying out rectification work following erection of the wall panel. Another disadvantage with known timber false formwork is that all of its components become waste product due to the fact that they cannot be re-used for moulding another concrete panel. Still further the installation of the timber false formwork must generally be carried out by a skilled person, e.g. a carpenter, which adds to the overall cost of moulding the panels.